Dynamic characteristic analysis of replenishing/leaking parallel valve control systems

Abstract

To improve the dynamic response of traditional pump control systems, this paper proposes two new control schemes: replenishing parallel valve control (RPVC) and leaking parallel valve control (LPVC). A parallel valve control system using the two control schemes is designed, and its system parameters, control performances and efficiency are analysed and verified by simulation and experiments. Compared to the pump control system, the proposed system has larger damping ratios which vary widely with operating points, and has lower velocity stiffness due to the increase of total leakage coefficients. Both the LPVC and RPVC could contribute to the dynamic response improvement. RPVC is preferred over LPVC because of more stable damping ratios and higher speed stiffness, and these advantages could be further improved by increasing the supply pressure of the control valve, but the LPVC scheme costs lower due to the unnecessary oil supply for the control valve. During the control process, the valve works at a low flow rate, but the pump provides the majority of the system flow, so two parallel valve control systems still have relatively high energy efficiency with rapid response. Therefore, the RPVC and LPVC will enrich the control mode of hydraulic systems.

Pressure-Relief Impact Control of Open Circuit Hydraulic Pump-Controlled Forging Press System

“…Consensus on the formation and development mechanism of pressure relief has not yet been reached. At present, researches mainly focus on the valve-controlled hydraulic press system, including analyzing the transmission rule of the pressure wave in the pipeline [19,20], proposing the active compensation method for the pressure-impact prediction of the directional valve [21,22], using the electro-hydraulic proportional cartridge valve as the pressure-relief valve [23], and designing an energy sinusoidal pressure-relief curve [24]. However, research on the pressure-relief process of pump-controlled hydraulic presses has rarely been reported.…”

The Influence of Valve-Pump Weight Ratios on the Dynamic Response of Leaking Valve-Pump Parallel Control Hydraulic Systems

“…where J is the equivalent total inertia, B m is the viscous damping coefficient, T L = D L P h is the load torque produced by the loading pump (ignoring the low-pressure chamber pressure) and D L = D m is the displacement of the loading pump. Combining (3), (5), (6), (7) and (8), the open loop dynamic equation for the LVPC [16] is given by:…”

Valve‐Pump Parallel Variable Mode Control for Complex Speed Regulation Processes

“…The valve-pump parallel variable model control system is made up of pump control circuit, valve control circuit, and hydraulic motor circuit [21]. In the section above, three control links will be established, respectively, and combined into a control block diagram.…”